The invention relates to a central vacuum power unit and more particularly to a central vacuum power unit allowing to substantially reduce the level of noise emitted.
A central vacuum cleaner comprises a power unit usually installed permanently in an area of a building and one or more ducts are connected to vacuum system intlets provided in various zone all over said building. Said cleaner allows to clean any areas of said building with the use of a flexible hose or other debris recuperation device connected to said intlets. Said central vacuum power unit can be activated by mere insertion of the hose in one of saids inlets which is electrically wire to said unit, or by a switch provided on the hose or in the debris recuperation device, or by any other means.
Because habitable surfaces in recent buildings are optimized, a central vacuum power unit is frequently installed near a living space. However, said power unit generates high levels of noise. Therefore, it is necessary to make said power unit as quiet as possible. The prior art reveals the use of opened cells polyurethane foam inside a canister of a vacuum cleaner, as sound absorbing material, the use of a muffler at the outlet of the working air; the flowing of sound through a tortuous passageway to generate sound reflection against sound absorbing material, the mounting of a motor on a seat made of vibration absorbing material, ect. Even with those characteristics intended to reduce the levels of noise emitted by existing central vacuum power unit, there is still a strong need for a more quiet central vacuum power unit for central vacuum cleaner.
More particularly, the prior art central vacuum power units suggest for reducing the level of noise generated at a vacuum air exhaust, to mount a straight silencer (muffler) to said exhaust of the working air. Preferably, it may be advantageous to provide an elbow between the an exhaust and the silencer to redirect the exhaust from a horizontal to a vertical direction and thereby to take less horizontal space (which is normally what is paid for in a building, ($/sq.ft)). Two problems arise in the prior art:
The use of a straight silencer fails to generate a sufficient amount of reflexion of said noise against a sound absorbing material and therefore a substantial level of noise is still emitted outside the central vacuum power unit.
The positioning of an elbow outside a canister of said central vacuum power unit creates an abrupt change in air direction that generates noise that is transmitted throught the sidewall of the elbow. This noise is not dampened in existing central vacuum power unit. Especially, when a tangential fan is used, the level of noise generated in the area of the elbow is important. Therefore, there is still a strong need fo find a simple and efficient way to reduce this prior art noise problem, especially to reach noise level lower than those of the existing prior art central vacuum power unit
It is to be noted that to seal leaks of noise originating from the opening around the working air exhaust, it is not possible to have a seal having at once no noises leaks and substantial surface properties (to block the noise) while remaining flexible. A more dense seal is generally less flexible. However, it is important to maintain the flexibility properties to avoid a rigid contact of the working air exhaust with the canister to avoid vibration and generating additional noise.
More particularly, said noise in the area of said elbow appears to have three origines, that is:
Opening around the fan outlet. Indeed, it was noted that even a very small opening will let considerable amount of noise escaping from the canister. Also, any vertical movement of the motor-fan assembly due to the vacuum underneath said assembly, contribute to increase the risk of having a solid contact with a structural part of the power unit to thereby transmit vibrations to said structure and generate additional noises (i.e. sound moves through the structure of the canister toward the outside)
Turbulence generated in said elbow (toward the outlet of the silencer). The zone of turbulence being near said silencer, the possibility of contact of the noise with a sound absorbing material is lowered.
Turbulence generated in the elbow (across the sidewall of the elbow) Standard elbow available in the industry are not provided with sound insulation and are generally made of light material such as polyvinyl chloride (PVC). They will let substantial amount of noise to propagate across its sidewall. Said sidewall has a low surface density and has low sound dampening properties.
It has now been discovered that the level of noises emitted by a central vacuum power unit for a central vacuum cleaner can be lowered, and preferably without affecting the efficiency and useful life of said power unit.
Advantageously, the present invention relates to a new central vacuum power unit, especially for a central vacuum cleaning system, said central vacuum power unit emitting substantially low level of noise outside in the surrounding environment Preferably, said level of noise are lower than those noted with existing central vacuum power unit
Advantageously, the present invention relates to a new central vacuum power unit, especially for a central vacuum cleaning system, in which the working air and noise (preferably at the fan exhaust) is subjected to at least one change of direction inside an acoustic dampening chamber, preferably to increase the amount of reflexions of the noise against sound absorbing material provided inside said acoustic dampening chamber.
Advantageously, the present invention relates to a new central vacuum power unit, especially for a central vacuum cleaning system, in which it is not necessary to use any outer silencer (muffler) or an elbow-silencer assembly at the working air exhaust of the power unit.
Advantageously, the present invention relates to a new central vacuum power unit, especially for a central vacuum cleaning system, that is simple, reliable and economical to manufacture
Advantageously, the present invention relates to a new central vacuum power unit, especially for a central vacuum cleaning system, that is very easy to install on a wall.
Advantageously, the present invention relates to a new central vacuum power unit, especially for a central vacuum cleaning system, in which the vacuum is a tangential vacuum fan, especially of the type having an axial air intake and a tangential air exhaust. Preferably, such a vacuum fan allow to generate an important vacuum and an important flow of working air
According to a particularly prefered embodiment of the invention, it has been surprisingly found that all important reduction of the level of noise emitted by a central vacuum power unit is obtained when the assembly is not positioned in the center of the canister, when the outlet of the fan enters a substantially annular acoustic dampening chamber and when the noise originating from the vacuum tangential fan has a change of direction and several absorption against a lining of sound absorbing material provided in said substantially annular acoustic dampening chamber.
According to another particularly preferred embodiment of the invention, means are provided to avoid the plate supporting the motor-fan assembly to tilt under the force resulting of the presence of a vacuum underneath the motor-fan assembly.
According to another particularly preferred embodiment of the invention, the motor-fan assembly and the piping at ist outlet do not have solid contact with the plate and/or canister supporting it, to thus prevent the transmission of vibration through the structure of the central vacuum power unit and thereby the gereration of noise.
According to another particularly preferred embodiment of the invention, the motor-fan assembly is centered to rest freely on a seat of vibration absorbing material thanks to a ring of vibration absorbing material retained in place by a ring of solid material making an integral part of the plate supporting the motor-fan assembly.
More particularly, the present invention relates to central vacuum power unit comprising in combination a canister, a chamber for collecting debris, a first plate, a second plate, a third plate, a duct means, a motor-fan assembly, a filtering means, a first baffle means, means for generating a flow of cooling air for an electric motor, and means for reducing the emission of noise outside the canister.
The canister has a sidewall and a hollow interior. The chamber for collecting debris may be in fluid communication with an inlet (preferably provided with an inlet) for a working air loaded with debris. The first plate extends across said hollow interior, is mounted to said sidewall and is provided with a first opening.
The second plate extends across the hollow interior and is provided with a first opening. The third plate extends across the hollow interior and is provided with a first opening. The duct means has a sidewall, a hollow interior, a first end and a second end. The first end is mounted on the first plate and has the hollow interior of said duct means in fluid communication with the first opening of the first plate. The second end is mounted to the second plate and has the hollow interior of the duct means in fluid communication with the first opening of said second plate. Said duct means supports the second plate above the first plate. The first plate and the second plate define with the sidewall of the canister and the sidewall of the duct means an acoustic dampening chamber. This acoustic dampening chamber is further provided with a lining of sound absorbing material and with an outlet in the sidewall of the canister.
The motor-fan assembly emitting noises and vibrations, rests freely against a seat made of resilient vibration absorbing material and is mounted on the third plate. Said motor-fan assembly comprises an electric motor, a vacuum fan provided with an axial intake in fluid communication with the chamber for collecting debris, a tangential outlet and a piping having a first end in fluid communication with said tangential outlet, and a second end in fluid communication with the inside of the acoustic chamber. Said motor-fan assembly generates a flow of working air from the inlet of the chamber for collecting, debris to the outlet of the acoustic dampening chamber.
Preferably, at the exhaust of the vacuum fan, an elbow, preferably facing downward, is placed to redirect the airflow to the substantially dampening acoustic dampening chamber. However, this substantially annular acoustic dampening chamber could be at any location, adjacent or not, to the motor-fan assembly.
The filtering means is positioned between the chamber for collecting debris and the air intake of the vacuum fan.
The first baffle means is provided inside the acoustic dampening chamber and is positioned to reduce direct motion delivered from the second end of the piping to the outlet of the chamber
The central vacuum power unit is advantageously characterized in that a portion of said piping passes across a further opening is provided in the plate which is provided with the seat of resilient vibration dampening material and is receiving the motor-fan assembly, in that said portion of piping has a vertical axis substantially parallel to the axis of the intake of the vacuum fan, so that any deformation of the seat due to the vacuum existing underneath the motor-fan assembly will allow the piping to slide freely in said further opening without solid contact with said plate.
According to a particularly preferred embodiment, the electric motor is further provided with a cooling fan forcing a flow of cooling air from one end of the electric motor to an opposite end of said motor, and said canister is further provided with a fourth plate extending across the hollow interior of the canister above the third plate, and a fifth plate extending across the hollow interior of the canister above the fourth plate. The fourth plate and the fifth plate define with the sidewall of the canister, a first chamber in fluid communication with a first opening provided in the sidewall of said canister and defining an inlet for the cooling air for the electric motor and a second opening across which a portion of a casing of said electric motor is engaged. The third plate and the fourth plate define with the sidewall of the canister a second chamber for the cooling air coming out the electric motor and evacuated outside the canister through an opening provided in the sidewall of the canister and in fluid communication with said second chamber
According to various embodiments of the invention, either the first plate and the third plate define the same plate, or the first plate and the fifth plate defines the same plate.
According to a more particularly preferred embodiment, the invention relates to a central vacuum power unit comprising in combination a canister, a debris collection chamber, a first plate, a second plate, a duct means, a filtering means, a motor-fan assembly, a first baffle means, means for generating a flow of cooling air for an electric motor, and means for reducing the emission of noise origination from the generation of said cooling air, outside the canister.
The canister has a sidewall and a hollow interior. The debris collection chamber is provided with an inlet for a working air loaded with debris. The first plate extends across said hollow interior, is mounted to said sidewall and is provided with a first opening. The second plate extends across the hollow interior and is provided with a first opening and a second opening.
The duct means has a sidewall, a hollow interior, a first end and a second end. The first end is mounted on the first plate and has the hollow interior of said duct means in fluid communication with the first opening of the first plate. The second end is mounted to the second plate and has the hollow interior of the duct means in fluid communication with the first opening of said second plate. Said duct means supports the second plate above the first plate. The first plate and the second plate define with the sidewall of the canister and the sidewall of the duct means an acoustic dampening chamber which is further provided with a lining of sound absorbing material and with an outlet in the sidewall of the canister.
The filtering means is positioned between the debris collection chamber and the duct means
The motor-fan assembly emits noises and vibrations rests freely against a seat made of resilient vibration absorbing material and is mounted on the second plate around the first opening of said second plate. Said motor-fan assembly comprises an electric motor, a vacuum fan provided with an axial intake in fluid communication with the first opening of the second plate, a tangential outlet and a piping having a first end in fluid communication with said tangential outlet, and a second end in fluid communication with the inside of the acoustic dampening chamber Said motor-fan assembly generates a flow of working air from the inlet of the debris collection chamber to the outlet of the acoustic dampening chamber.
The first baffle means is provided inside the acoustic dampening chamber and is positioned to prevent direct motion of noise delivered from the second end of the piping to the outlet of the acoustic dampening chamber.
Preferably, the central vacuum power unit according to the invention is characterized in that a portion of said piping passes across the second opening of the second plate and has a vertical axis substantially parallel to the axis of the intake of the vacuum fan, so that any deformation of the seat due to the vacuum existing underneath the motor-fan assembly will allow the piping to slide freely in the second opening of the second plate without solid contact with said second plate. Preferably, the deformation and the motion are substantially vertical.
Advantageously, there is a pathway between the outlet of the piping and the outlet of the acoustic dampening chamber that represents a portion of circle. Preferably, said pathway is substantially annular.
Preferably, the duct means has a substantially vertical passage between its first end and its second end, the first end being substantially co-axial with the first opening of the first plate, the second end being parallel and not aligned with the first opening of the second plate
Preferably, the acoustic dampening chamber and first baffle are completely provided with a lining of sound absorbing material.
Preferably, a sleeve of resilient vibration absorbing material is mounted around the second opening of the second plate. Said sleeve may have an interior of such size and orientation to allow a free axial sliding of said portion of the piping passing across the second opening of said second plate while substantially preventing leak of working air and noise from the acoustic dampening chamber. Advantageously, said sleeve may be mounted on an upper side of said second plate. More preferably, said sleeve is mounted by gluing.
Preferably, the electric motor may be further provided with a cooling fan forcing a flow of cooling air from one end of the electric motor to an opposite end of said motor, and said canister may be further provided with a fourth plate extending across the hollow interior of the canister above the second plate, and a fifth plate extending across the hollow interior of the canister above the fourth plate. The fourth plate and the fifth plate define with the sidewall of the canister a first chamber in fluid communication with a first opening provided in the sidewall of the canister and defining an inlet for the cooling air for the electric motor and a second opening across which a portion of a casing of said electric motor is engaged The second plate and the fourth plate define with the sidewall of the canister a second chamber for the cooling air coming out the electric motor and evacuated outside the canister through an opening provided in the sidewall of the canister and in fluid communication with said second chamber.
Advantageously, the fourth plate may be sat on a portion of the sidewall of the canister projecting toward the hollow interior, in order to position it above said second plate
Advantageously, the fifth plate may be a cover adapted to close one end of the canister.
Preferably, a set of second baffles may be further provided between the inlet opening of the canister and the second opening of the fourth plate. Advantageously, said second baffles are provided with a lining of a sound absorbing material.
Preferably, the second chamber may be provided with a lining of sound absorbing material.
Preferably, the inlet of the second chamber and the outlet of the third chamber may be each provided with an outer muffler provided with a lining of sound absorbing material therein. Advantageously, both mufflers may be provided in a hollow member having parallel conduits, each conduit being in fluid communication with the exterior of the canister at opposite ends of said member, and being respectively in fluid communication with the inlet of the first chamber and the outlet of the second member.
Preferably, said hollow member may be further provided with means for hanging the central power unit to a wall.